Your mind will conjure up a long list of potential things that may go wrong

...so

choose the worst top three potential problem and create anticipated solutions - "I'm sure I'll forget my words"; "No, hang on - I have my speech outline on key cards to help me through any tricky moments"

You may feel a little wary of your audience initially

...so

it helps to arrive relatively early and chat informally to some individuals in your audience - you'll see that they are sensible people who are interested in what you have to say

You may feel that you are not qualified or knowledgeable enough to present this address to your audience

...so

prepare you content exceptionally well and remember that you are the expert - after all they invited you to speak to them today

You may want to rush up and "get this over and done with"

...so

don't! Take your time as you walk to the podium; take a moment to look at your audience; take one or two deep breathes - pause to collect your opening line - and only then should you begin speaking